Mike Novak and Rachelle LeFevre are on the right side of the “Dome.” (CBS)

Rachelle Lefevre, the stunning redhead at the center of CBS’ summer thriller, “Under the Dome,” recently found herself staring at the story’s author, that master of mayhem, Stephen King.

King was on set in Wilmington, North Carolina to observe the ensemble cast try to cope in a brave, new, twisted universe when their idyllic small town, Chester’s Mill, Maine, is suddenly cut off from the outside world by a massive, see-through, impermeable dome. Touch it and your pacemaker goes on the fritz. Shout and realize that no one can hear you. Try using your cell to connect to the outside world and find it is no longer operable. It’s like living in a killer snow globe.

So Lefevre, best known for playing blood-sucker Victoria Sutherland in the first two parts of the “Twilight” trilogy, was naturally curious about the mind behind the source material, the novel, first published in 2009.

“There is something strange about him,” she says of King, one of the series’ executive producers. “He’s so nice and friendly, completely unassuming. But one thing I’ve tried to reconcile is: How is it possible for a person who seems so balanced, to write this?”

Lefevre, 34, plays the town’s tough-minded newspaper editor, Julia Shumway. Getting into character, she started asking King questions. “And he said that when he conceived ‘Under the Dome,’ he was sitting on an airplane, and it was this idea of how we are all alone on planet Earth, that we are essentially all under a dome as far as the universe is concerned. He started thinking about this idea of diminishing resources, and that when the s–t hits the fan, human beings are capable of literally devouring one another for survival. It’s not that he’s horrific, but that we are.”

The television series is not entirely faithful to the book. The biggest gripe among King fans, who have been vocal on the Internet, by far is making the Barbie character, an Army veteran played by Mike Vogel, into a villain; in the book, he did not commit murder and bury a body in the woods before the dome descended. Other complaints involve the reaction of the citizens in Chester’s Mill to diminishing resources. The 13-part series rolls out at a pace of about one day per episode, meaning that by the end, we will have witnessed the first two weeks of a populace cut off from food, water, and, most chillingly, air. So far, no one’s panicking, prompting even the actors to question their producers.

“That is one of the things that we were asking in the beginning,” says Lefevre. “And the answer was: People are not that pragmatic and not that calm. If you look at any crisis there are two factors really at work: First, fear completely paralyzes our ability to be rational and sensible. No one says, ‘We have to save water!’ And the other thing that gets in the way is denial: Maybe this won’t be so bad.”

Despite the protests, the series has become an instant summer hit, catapulting Lefevre, who has been acting since the age of 18, into the spotlight. A native of Montreal, Lefevre’s father is an English teacher of French and Irish extraction. Her mother is a psychologist and Jewish. Lefevre’s parents divorced when she was very young; her mother remarried and her stepfather is a rabbi.

How would Lefevre react if she, herself, were trapped under a dome? “I have my mother’s personality in a crisis,” she says. “She’s extremely levelheaded. So I would be one of the first people to start figuring out what to do.”

In real life, living under the “dome” for Lefevre has been wonderful. She has been sharing the experience with her boyfriend, Chris Crary (voted “Fan Favorite” on Season 9 of “Top Chef”). “When I booked this show, we wanted to spend some time together, so he’s hanging out here with me and then when I’m done with the show, he’ll go back to work.”

The two met last September in the most modern of ways.

“He asked me out on Twitter!” she says. “He tweeted me and invited me to the restaurant. He was working at the Viceroy in Santa Monica. He was the chef de cuisine. It was a public place, and it felt safe, and he was cute. And so I went to the restaurant and actually ate his food for an hour before I ever met him. So I kind of really liked him before I really liked him. It’s so bizarre.”

What possessed her to go? “We joke about it now,” says Lefevre. “He says, ‘I can’t believe you came. What kind of a crazy person comes when somebody says on Twitter, “Come to the restaurant?” I don’t know, I just had a feeling.”

It’s not the first time that being in a restaurant has led to a lucky break. Lefevre has her own Lana Turner-like story of being discovered, not at Schwab’s drug store, but at a Montreal sushi restaurant where a Canadian producer overheard her saying that she wanted to be an actress. He arranged for an audition, which led to Canadian television and film roles, interspersed with four years of study at McGill University, where she is just shy of having enough credits to fulfill her goal of having a backup career as a high school teacher.

But that all changed when she was cast on a short-lived 2005 Fox sitcom, “Life on a Stick.”

“We were canceled after five episodes,” she says. “But they relocated me to Los Angeles and the job paid enough that I thought, ‘I’ve got 13 episodes’ worth of paychecks and I’ll get an apartment. If the money runs out, and I need health care again, I’ll go home to Canada.’”